Field of the Invention
The present invention relates to a robot apparatus, an exchanger apparatus and a robot system capable of exchanging an operating unit that operates an operating object.
Description of the Related Art
In recent years, work such as assembling and processing of industrial products having a small-size complicated structure, such as a camera and a printer, is automated. Components used for industrial products of this type are small-size precision components in many cases, and have a wide variety of shapes.
Meanwhile, it is required to consecutively manufacture various kinds of products using a single robot apparatus, and, in manufacturing sites, a step change including exchanging end effectors and tools of the robot apparatus according to a workpiece type and a process flow change is necessary in more and more scenes. Efforts and working time are required for a worker to manually change the configuration of the robot apparatus of this type, and hence there is an increasing demand for a so-called automatic step change in which a step change is performed by programming of the robot apparatus as much as possible.
Under the circumstances, robot apparatuses are required to have a small-size and simple configuration as well as specifications and performance that enable gripping of a wide variety of workpieces and work such as assembling and processing. At the same time, it is desired to: automatically exchange tools for gripping of workpieces and work such as assembling and processing, without the need for work and assistance by a worker; perform an automatic step change by changing the apparatus configuration as little as possible; and enhance the operating rate of the entire robot apparatus.
With regard to the automatic exchange of an operating unit (such as the tools (end effectors) of the robot apparatus and constituent elements of the tools), it is required to reduce the size and weight of each tool, shorten the time to exchange one of the tools and the constituent elements thereof, and enhance the attachment accuracy at the time of the exchange. The tools (end effectors) include a (robot) hand for gripping/transportation, a spray gun for paint application, a welding machine and various other apparatuses, and are exchangeable with respect to a (robot) arm according to a workpiece type and a process flow change. Moreover, in the case of a tool such as a (robot) hand, portions of fingers (which may be referred to as tweezers) for handling a workpiece are exchangeable in some cases. In particular, in order to exchange the portions of the fingers of the hand, such structures as described in Japanese Patent Application Laid-Open No. 2009-125867 and Japanese Patent Application Laid-Open No. 2013-091121 are proposed. For example, in a hand apparatus of an industrial robot described in Japanese Patent Application Laid-Open No. 2009-125867, a nail lock mechanism at a hand leading end is released by an arm movement, whereby old fingers are detached. Then, new fingers are attached by a similar process on the lock mechanism and a similar arm movement. In an exchanging module for a robot hand described in Japanese Patent Application Laid-Open No. 2013-091121, modularized fingers are attached and detached with respect to a hand, whereby the plurality of fingers can be collectively exchanged.
The configuration described in Japanese Patent Application Laid-Open No. 2009-125867 has a problem that: each of finger detachment and finger attachment requires one arm movement; and the finger exchanging motion thus takes time. Japanese Patent Application Laid-Open No. 2009-125867 does not particularly devise how to enhance the positioning accuracy in coupling.
In general, there is a limit on the positioning accuracy of a robot arm, and a positioning error occurs in the operation position of a fingertip. Hence, in the case of attaching a tool by a motion of the robot arm, it is necessary to provide a certain dimensional allowance (clearance) between a tool attaching portion and a tool attached portion. Particularly in the case of repetitively performing an automatic tool exchange, the possibility that mispositioning might occur in a coupling portion within the range of this dimensional allowance remains.
Meanwhile, according to the technique described in Japanese Patent Application Laid-Open No. 2013-091121, when a finger module is first attached to the hand, the attachment is possible by one arm movement. However, in the case of repetitively exchanging different finger modules, Japanese Patent Application Laid-Open No. 2013-091121 has a problem that: a motion of detaching one finger module and then attaching another finger module needs to be performed several times; and the exchanging motion thus takes time. Japanese Patent Application Laid-Open No. 2013-091121 has another problem that: a mechanism for forming finger modules is necessary; the size of the entire hand is increased by attaching a finger module thereto; and the weight of the entire apparatus is larger.
The present invention has an object to enable easily exchanging an operating unit such as tools of a robot apparatus and constituent elements of the tools, without the need for manual work and assistance by a worker, while adopting a simple, inexpensive, small-size and light-weight configuration.